The FDA says Botox injections have been shown to be effective in the prevention of migraines, which are debilitating headaches that cause intense pulsing or throbbing pain and affect about 12% of Americans.

“Chronic migraine is one of the most disabling forms of headache,” Russell Katz, MD, of the FDA, says in a news release. “Patients with chronic migraine experience a headache more than 14 days of the month. This condition can greatly affect family, work, and social life, so it is important to have a variety of effective treatment options available.”

Migraine headaches are sometimes called “sick headaches” because they often are accompanied by nausea and sensitivity to light and sound.

How Botox Is Used to Treat Migraines

Botox to treat chronic migraines is given at intervals of about 12 weeks as multiple injections around the head and neck to try to dull future headache symptoms, the FDA says in a statement.

The FDA says it’s important that patients who suffer chronic migraines discuss with their doctors whether Botox is appropriate for them.

Allergan Inc., the maker of Botox, says in a statement that the FDA’s approval applies to people with chronic migraine, which it defines as a “distinct and severe neurological disorder characterized by patients who have a history of migraine and suffer from headaches on 15 or more days per month with headaches lasting four hours a day or longer.”

The company says that when treating chronic migraine, qualified medical specialists administer 31 Botox injections into seven specific head and neck sites.

It says that Botox, when injected at labeled doses in recommended areas, is expected to produce results lasting up to three months depending on the individual patient.

Botox Studies

“Chronic migraine is a debilitating but under-recognized neurological condition,” Scott Whitcup, MD, Allergan’s chief scientific officer, says in the company’s announcement. “Oftentimes, chronic migraine patients mistakenly self-diagnose their symptoms as headaches or infrequent migraine and treat them with drugs that provide rapid, but temporary, relief rather than seeking an evaluation, diagnosis and treatment from a qualified headache specialist.”

He says with the FDA’s approval of Botox to prevent migraines, there is now a new option “to reduce the days and hours spent in pain as a result of this condition.”

It says the FDA’s approval for use of Botox to fight migraines was based on the results of two studies involving 1,384 adults in North America and Europe.

The studies, published in the March 2010 issue of Cephalalgia, report that patients treated with Botox experienced a major decrease in the frequency of headache days, according to the Allergan statement.

Botox Side Effects

The most common adverse reactions reported by patients being treated for chronic migraine have been neck pain and headache, the FDA says.

The FDA also has placed a “boxed warning” on the anti-migraine drug, onabotulinumtoxinA, marketed as Botox and Botox Cosmetic. The warning says the effects of the botulinum toxin may spread from the area of injection to other areas of the body, causing symptoms similar to those of botulism.

These symptoms can include swallowing and breathing problems. The FDA says it knows of no confirmed cases of the spread of the toxin effect when Botox has been used at the recommended dose to treat chronic migraines, severe underarm sweating, or conditions such as blepharospasm, an involuntary muscle spasm in the muscles surrounding the eyes.